Ultra-high frequency electric discharge device



May 19, 1959 2,887,602

ULTRA-HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE G. TUCKER Filed June 19. 1956 INVENTORZ JEWELL G.TUCKER,

BYwaR w ms TORN FIG.4.

FIG.3.

United States Patent ULTRA-HIGH FREQUENCY ELECTRIC DISCHARGE DEVICE Application June 19, 1956, Serial No. 592,380

9 Claims. (Cl. 313-174) My invention relates to electric discharge devices and pertains more particularly to a new and improved ultrahigh frequency electric discharge device adapted for operating with minimum power losses.

In the operation of electric discharge devices, electric and magnetic fields are generally established and maintained about the mount structures including the cooperating electrode elements; and it is known that introduction of materials, such as conductive elements, in such fields results in a coupling effect whereby an impedance is re flected back on the source or operating circuitry. In ultra-high frequency devices, such for example as ultrahigh frequency oscillator triodes, this reflected impedance can be relatively substantial and act in associated circuitry as an undesired or secondary load and thus decrease substantially power output to a desired or primary load. Viewed from another standpoint, the undesired or secondary load can reduce the sharpness of resonance and the reactive component of the impedance can adversely affect resonant frequency. The resistance also tends to vary the resonant frequency, especially where the sharpness of resonance is relatively high. It has been found that the magnitude of the reflected impedance is a function of conductivities, dielectric constants and permeabilities of materials disposed in the effective coupling ranges of the electric and magnetic fields and comprising the secondary load, relative positioning of the materials comprising the secondary load and the fields source, and a function of the operating frequency squared.

A primary object of my invention is to provide a new and improved ultra-high frequency electric discharge device.

Another object of my invention is to provide a new and improved ultra-high frequency electric discharge device including means adapted for minimizing power losses resulting from undesired reflected impedance.

Another object of my invention is to provide a new and improved getter support assembly adapted for use in electric discharge devices and minimizing power losses resulting from coupling in the devices with the materials of the assembly and getter flash materials.

Further objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming part of this specification.

In carrying out the objects of my invention I provide an electric discharge device adapted for operation at ultrahigh frequencies and including an envelope containing electrode means. The envelope includes a region which is substantially devoid of material and wherein electric and magnetic fields are established and maintained during operation of the device in an appropriate circuit. Further included in the envelope is a dome portion disposed outside of the mentioned void region and beyond the effective coupling range of the fields therein. Other materials contained in the envelope such as the getter Patented May 19, 1959 assembly and getter flash material are isolated and confined in the dome portion.

For a better understanding of my invention reference may be had to the accompanying drawing in which:

Fig. 1 is an enlarged partially sectionalized elevational view of an electric discharge device constructed in accordance with the teachings of one embodiment of the present invention;

Fig. 2 is a top plan view of the device with part of the envelope broken away;

Fig. 3 is an enlarged fragmentary partially sectionalized view illustrating a modified form of the present invention; and

Fig. 4 is an enlarged fragmentary partially sectionalized view illustrating another modified form of the present invention.

Referring to Figure 1, there is shown an electric discharge device of the ultra-high frequency type generally designated 1 and comprising an evacuated cylindrical envelope 2 containing a tube mount structure or electrode support assembly 3. The mount structure 3 includes a pair of spaced insulative support members 4 which can be mica disks or the like. Supported between the members 4 and arranged substantially coaxially are electrodes comprising a cathode 5, a grid structure 6 and a plate or anode structure 7. As seen in the drawing, and owing to the adaptability of the present device to ultra-high frequency operation, substantially close spacing is provided between the various electrode elements. For example, the plate 7 is formed with oppositely disposed and inwardly extending portions 8 thereby to provide the required close spacing between the grid and plate.

The envelope 2 includes a base portion generally designated 10 through which is sealed a plurality of prongs or lead pins 11. As shown, leads 12 are provided in the envelope 2 for affording required connections between the various electrode elements and appropriate ones of the prongs 11. Thus, the mount structure 3 is suitably electrically connected to the leads and the structure is supported in the envelope 2 in a portion thereof adjacent the base portion 10.

During operation of the device 1 in an appropriate system or circuit (not shown) electric and magnetic fields are established and maintained about the mount structure 3. These fields extend into an intermediate region of the envelope which may be considered as substantially defined by the dot-and-dash lines 13 in Figure 1.

Now, I have found that in the operation of ultra-high frequency devices of the type described above and illus trated in the drawing, power output losses or losses in the primary or desired load result when materials are introduced into or disposed in the region 13 or, more specifically, the electric and magnetic fields occupying the region 13, which losses vary with the material and are greater when the material is conductive. The mentioned losses are understood to be caused by reflected impedance resulting from effective coupling between the material and the fields in the region 13. The reflected impedance acts in the operating system or circuitry as an undesired or secondary load, absorbing power and thus reducing the power available for the desired or primary load. Additionally, the magnitude of such impedance is considered to be a function of the conductivity, dielectric constant, permeability of the material constituting the secondary load, the position of this material relative to the source of the fields, and a function of the operating frequency of the device squared. The field strength of radiated energy varies inversely in a non-linear manner with the distance from the radiating source. Byarranging no material in the region 13, which is adjacent to a radiating source; i.e., the electrode structure 3, I increase the distance beasst-ma tween, the electrode structure 3 and other materials required in the envelope 2. Thus there is no material within the eflective coupling range of the electric and magnetic fields setup by the electrode structure during operation of the tube. TherefonefI- prevent the coupling of electric and magnetic field to materials within the envelope 2, which would act as an unmatched load on the operating system and reflect impedance to the electrode structure 3, thereby loading the electrode system and decreasing the efficiency of the tube.

Accordingly, I have constructed the envelope 2 to include a dome portion. 14 which is located. outside of the region 13 and thus beyond the .eifective coupling range of the electric. and magnetic fields normally occupying the region 13.. Disposed in the dome 14 are other materials required in the device 2 and which if located in the region. 1.3- would tend to couple with the fields and result in reflected impedance. back on the source, causing an unwanted load in the system and power losses in. the desired load.

Specifically, and according to one embodiment of the present invention. I have provided in the dome portion, 14 a getter support. structure generally designated 15. The structure 15 comprises an insulative shield member 16 which, as seen in Figure 2, may comprise a conventional mica disk similar in structure to the insulative support members 4 in the mount structure 3 and including a plurality of circumferentially spaced points or snubbers 16a engaging the internal side walls of the envelope. As seen the member 16 substantially compartmentalizes the dome portion of the envelope. In the embodiment shown in Figures 1 and 2, the member 16 is provided with a centrally disposed aperture having a metallic eyelet 17 fitted therein, Secured to the eyelet 17, as by spot-welding, and extending vertically in the dome is a support rod 18. The support rod 18 includes a; hooked portion 19 adapted for being embedded in the upper portion of the dome 14 whereby the structure 15 is supported from the upper end of the dome 14. The hook 19 may be embedded in the dome during the customary tip-oif operation following evacuation of the envelope.

Secured to the rod 18 between the disk 16 and the upper end of the envelope dome, as by spot-welding also, is a transversely extending support member 20. Secured on the member 20 as by spot-welding is a U-shaped getter support 21 between the open ends of which is suitably secured the gettering material 22 which may be in strip form as shown and of any well-known gettering substance.

When the gettering material 22 is flashed in the usual manner after sealing of the device and as by inductive heating, the internal surface of the dome portion 14, or the portion of the envelope between the member 16 and the upper extremity of the envelope becomes deposited with the usual silvery, metallic getter flash material indicated at 23. The eyelet 17 and spaces provided between the edge of the member 16 and the envelope wall permit required communication between the substantially compartmentalized dome 14 and the rest of the en velope to provide for effective gettering of the device. However, the member 16 additionally serves as a shield for avoiding substantial deposits of the silvery material 22 on the envelope wall or device elements outside of the dome portion 14.

More specifically, the member 16 substantially confines the flash material 23 within the dome portion 14 and avoids any substantial deposit thereof on the walls of the envelope in the region 13 or elsewhere in the device wherein it would be in the effective coupling range of the electric and magnetic fields and would result in undesired reflected impedance and power losses during operation of the tube.

Additionally, itwill be seen from the foregoing and the drawing that in the present arrangement the region 13 is also devoid of support structures or the like for the getter support assembly and the member 16 and all of the getter support structure including the member 16 are confined to the dome portion 14 beyond the effective coupling range of the electric and magnetic fields extending into the region 13. Thus, reflected impedance and power losses are further reduced.

Illustrated in Figure 3 is a modified form of the present invention wherein the envelope structure 2 including the dome portion 14 is. substantially identical to that described above with regard to Figure 1 and the dome portion is located outside of the region 13 or, in other words, beyond the elfective coupling range of the electric and magnetic fields established about the field source thisembodiment, however, the member 20 is spot-weldedv to a central support rod 26 which is spot-welded to the eyelet 17 and terminates short of the upper end of the dome. The structure 25 is supported in the dome portion 14 of the envelope by means of inwardly projecting portions of the envelope 27 disposed on the side of the structure 25 opposite the dome portion 14. The portions 27 may be provided in any suitable manner, as by providing quantities of glass frit at appropriate positions in the tube after the structure 25 is in place and before the base 10 is sealed into the tube bulb and heating such trit in, order to effect fusion thereof in the desired locations. the structure 25 in the position illustrated in Figure 3. In this position the gettering material strip 22 is flashed, resulting in the flash material deposit 23. Additionally, in this position of the structure 25 and with the material 23 substantially confined or isolated in the dome portion of the envelope the device is adapted for operating with reduced power losses in the manner described above with regard to the device illustrated in Figure 1.

Illustrated in Figure 4 is another modified form of the present invention wherein the envelope structure and getter support structure may be identical in construction and purpose to that illustrated in Figure 3. In this embodiment, however, the getter support structure 25 may be suitably retained inv the dome 14 by reducing the diameter of the envelope 2 just beneath the dome 14 or on the side of the member 16v opposite the dome 14 and immediately adjacent the member 16. As illustrated in the drawing, this reduction of the diameter of the envelope can be effected by playing a pin fire or flame,

generally indicated at 29, against the wall of the envelope thus to collapse the wall a slight degree in this region while the envelope is being rotated about the longitudinal axis thereof. Following retention of the structure 25 in this manner the gettering material strip in the structure 25 may be flashed, and the resultant flash material will be substantially confined to the dome portion of the envelope.

While I have shown and described specific embodiments. of my invention, I do not desire my inventionto be limited to the particular form shown and described. and I intend by the appended claims to cover all modifications Within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An ultra-high frequency electric discharge device comprising; an insulative envelope, electrode means and mounting means therefor in said envelope and comprising a source of electric and magnetic fields during opera, tion of said device, and said device having substantially Thus, the portions 27 are effective for retaining.

all other materials therein disposed in said envelope substantially beyond the effective coupling range of said fields and separated from said electrode means and mounting means by a substantial void, thereby to minimize undesired reflected impedance and resultant power losses in the operation of said device.

2. An ultra-high frequency electric discharge device comprising; an insulative envelope, an electrode mount structure including conductive leads therefor in said envelope and comprising a source of electric and magnetic fields during operation of said device, and other material in said envelope including a getter assembly and gettering material deposited on the internal walls of said envelope, all of said other material being spaced from said mount structure and located in said envelope substantially remote from said mount structure and beyond the effective coupling range of said fields, thereby to minimize undesired reflected impedance and resultant power losses in the operation of said device.

3. An ultra-high frequency electric discharge device comprising; a cylindrical insulative envelope, electrode means and mounting means therefor in said envelope adjacent one end thereof and comprising a source of electric and magnetic fields, said envelope including a void intermediate region wherein said electric and magnetic fields extend during operation of said device, and said device having substantially all other material therein disposed in the other end of said envelope substantially beyond the effective coupling range of said fields in said intermediate region for minimizing undesired reflected impedance in the operation of said device.

4. An ultra-high frequency electric discharge device comprising; a cylindrical insulative envelope including oppositely disposed base and dome portions, electrode means in said envelope adjacent said base portion and comprising a source of electric and magnetic fields during operation of said device, said dome portion being located substantially beyond the effective coupling range of said fields, and a getter assembly supported by and confined in said dome portion thereby to minimize undesired reflected impedance efiects thereof on the operation of said device.

5. An ultra-high frequency electric discharge device comprising; an envelope including oppositely disposed base and dome portions, electrode means in said envelope adjacent said base portion and comprising a source of electric and magnetic fields during operation of said device, said dome portion being located substantially beyond the efiective coupling range of said fields, a planar member solely supported by said dome portion and extending transversely therein, said member supporting a getter assembly and being eflective for confining substantially all getter flash material in said dome portion thereby to reduce power losses in the operation of said device.

6. An electric discharge device comprising; an envelope including oppositely disposed base and dome portions, electrode means in said envelope adjacent said base portion and comprising a source of electric and magnetic fields during operation of said device, said dome portion being located substantially beyond the effective coupling range of said fields, an element embedded in said dome portion and extending into said envelope, 9.

member supported from said element and extending transversely in said dome portion, and a getter assembly and getter flash material in said device confined by said member in said dome portion and thus disposed beyond said coupling range of said fields thereby to minimize power losses in said operation of said device.

7. An electric discharge device comprising; an envelope including oppositely disposed base and dome portions, electrode means in said envelope adjacent said base portion and comprising a source of electric and magnetic fields during operation of said device, said dome portion being located substantially beyond the effective coupling range of said fields, a member extending transversely in said dome portion, said dome portion including inwardly extending portions retaining said member therein, said member supporting a getter assembly and confining substantially all getter flash material in said device in said dome portion, thereby to minimize reflected impedance efiects thereof in the operation of said device.

8. An electric discharge device comprising; an envelope including oppositely disposed base and dome portions, electrode means in said envelope adjacent said base portion and comprising a source of electric and magnetic fields during operation of said device, said dome portion being located substantially beyond the effective coupling range of said fields, a member extending transversely in said dome portion, said envelope being reduced in circumference on the side of said member remote from said dome thereby to retain said member in said dome portion, said member supporting a getter assembly and confining substantially all getter flash material in said device in said dome portion, thereby to minimize reflected impedance effects thereof in the operation of said device.

9. An ultra-high frequency electric discharge device compromising; a cylindrical insulative envelope including oppositely disposed base and dome portions, electrode means confined in said envelope to a portion thereof adjacent said base portion and comprising a source of electric and magnetic fields during operation of said device, said dome portion being substantially spaced from said electrode means and thus located substantially beyond the effective coupling range of said fields, and a getter assembly comprising a planar transverse member having only a single perforation and supporting a quantity of getter material, said getter assembly being solely supported by and confined in said dome portion thereby to minimize undesired reflected impedance efiects thereof on the operation of said device.

References Cited in the file of this patent UNITED STATES PATENTS 1,817,445 Robinson Aug. 4, 1931 2,067,817 Beggs Ian. 12, 1937 2,082,851 Smith June 8, 1937 2,112,082 Espe Mar. 22, 1938 2,122,932 Dutfendack et al July 5, 1938 2,354,946 Cohen Aug. 1, 1944 2,476,940 Wood July 19, 1949 2,556,855 Stutsman June 12, 1951 2,653,264 McLinden Sept. 22, 1953 

